The US has called on the Gulf states to "de-escalate" their row with Qatar, saying it has caused unintended "humanitarian" consequences.

Secretary of State Rex Tillerson urged Saudi Arabia and other states in the region to ease their blockade of the peninsula, saying it was affecting the US-led fight against Islamic State.

He also said it was hurting American business in the area.

Mr Tillerson said: "Our expectation is that these countries will immediately take steps to de-escalate the situation and put forth a good faith effort to resolve their grievances they have with each other."

He admitted that the Emir of Qatar needs to do more to limit terrorist funding but said he has made progress.

Five countries - Saudi Arabia, Egypt, the UAE, Yemen and Bahrain - cut diplomatic ties with Qatar on Monday over allegations that Doha is supporting Islamist groups and courting Iran.

Video:6 June: Arab states cut Qatar ties over terror links

They are united in their fear Qatar's alleged ambivalence towards Tehran and were galvanised by US President Donald Trump's recent tour of the region.

The closure of Qatar's only land border, with Saudi Arabia, has raised fears of the country running out of supplies for its 2.7 million people, with long queues forming at supermarkets which are struggling for food stock.

Mr Trump said Qatar has historically been a funder of terrorism at a "very high level" and that he had decided it was time to call on the country to stop.

Mr Trump told reporters at a White House news conference with the Romanian President: "No civilized nation can tolerate this violence or allow this wicked ideology to spread on its shores."

It came as Donald Trump spoke with Egyptian president Abd El Fattah El Sisi about the importance of maintaining unity among Arab countries.

Video:21 May: Trump seeks coalition to 'stamp out extremism'

The White House said the Mr Trump and Mr Sisi agreed on the importance of all countries implementing agreements to fight terrorism.

The Pentagon said it agreed with Mr Tillerson's analysis of the impact of the blockade.

A spokesman said that, while military operations against Islamic State from Qatar had not been interrupted, the "evolving situation is hindering our ability to plan for longer-term military operations".

Captain Jeff Davis, a Pentagon spokesman, said: "While current operations from Al Udeid Air Base have not been interrupted or curtailed, the evolving situation is hindering our ability to plan for longer-term military operations."

Qatar's Al Udeid Air Base is home to more than 11,000 US and coalition forces and an important base for the fight against IS.